Trench digger blade construction



Aug. 15, 1950' F. J. SCHMIDT TRENCH DIGGER BLADE CONSTRUCTION OriginalFiled June 20. 1947 2 SheetsSheet 1 \lii Ill

t hm mm m c V NJ Aug. 15, 1950 F. J. SCHMIDT TRENCH DIGGER BLADECONSTRUCTION Original Filed June 20, 1947 2 Sheets-Sheet 2 INVENTOR.Friedrich J Schmidt Patented Aug. 15, 1950 2,519,01TRENCHnisenn.BLADnCQNSIMLQTJQN sFriedrichxl'. Schmidt, Auburn, Nebn,assignorlto Auburn Machine Works, lnc iOmaha, :Nfibr.,;a, iceiporation-of Nebraska "Original "application June 32;}, 13 s fl i-55 825.*Divided'and this-am'glication dctober 28,"19 i9,'SerialNo.124,047

.1 Claim. .1 ifllhiszinvention pertain to trench diggers and more;=pa1zticu arly :to an mprove eonstruction andra an ementofdiggerrblades.

An object of this invention is to provide im- 32 concre e may The manned:dire l-y :fOr nonst u in fimilding fennda ienath re ylimin ti ertheLifiQeQf forms enerally -srequir.ed in :the w k.

completing :ihe rde isn 20f th re n a pmved \di e eblade moun d on an(endless 15 ehinenamew muttin 'andeleva ne p c pl has dtivenfih in:end menstructed and arr nged been devised. \Itiha ibeen fcundthathycurvmate-successive blades have :different amounts of ing;andsharpenin aseries of -steelcutting' blades lateral-bit causin iearthtoibe-removed-progresin Q e ma r t b l t u y discloged SiVeIY and y. :1J 5 a d bj t and mounting "them for edgewisemovement onprovide'bladeswhichi l z q tucted d mou an -endlessiconveyor{chain :theiblades notonly ed-inaa novehmanner lnot'on v ineth e cut tl'ge ggrqlgndEhut @ISOQQIIGYQJZE theiexcavated ting qperation-qtopbersmeoth andrelatively free mflterifllgto gthe surface,(completelyeliminating ofshockqend ll bmtiongunderra-xvide-variety of themse of seeops, packetsand-the like. :As an earth zconditions :;b.ut also a causing atheloosened additional feature the :blades ere s designed earthtohesguioklyan c nflvd a that tl e ;=1jlee1'tl?l er.9f,-WhiCh is {theside-of the thegsurface. saidb-ladebppmit the-cutting edge rests onitheFurther YODJ C TS ra f tures of novelty will chaimlinkimmediatelygadjacent lI-hisprovides becomeappareni fl ofthoseskilled-.in-the artinihe a bearing surface for the blade inaddition tofollowing dS iptifln not the preferredembodiits actuahmonnting on thehain. menw d h p e ent ti l ufit the v2 iznefeerrin zmw its thez-ii 3wines,a smal c accompanying d wi g i veritiena zvehie e Al imm d at lyrecogni a wEieur 1 5e g n a i w i elevation 'Q a asasonventi na eeep frm-an insp e of Fi enc er ,rhav g c111 endless z-dig g chain 430 Liisutilized @StflgRQWQT source. Arframeicr supwhich .the present inventionis-applicable. port prcvided en @the y'rea-r portion-of :the ve- Fi g.laiisea re r yiew-erthe-treneher oeFis. hicleland eenerallydn a e by e'e f e-Eig. is ea detailed view 4 of 1a length of digger numeral 11-2.(A mower wtake-off -shait it ,e-xtends chain!incorporat ng-tmprovedblade ns u fr m th itransm s ien zrea wa v {into ta m w tion. tak-el s eXJ6leonventi allv kn :Fig. 53 is it aside w ew ref 2 1 n shown inhel wulley dri e- Fig. 12. Pivotally mounted on the frame I 2 for foreailt Fig.4 iszasectionahview of :the chain andsupporting-beamitakemalongthe line le -chime. 1.

zEig. 25 :is an elevational side wv-iew 1 of one of the cutter blades.

Figs. i=6, "2'1, .8 .anidl Bare *transverse sectional views taken inFig. 2 along the lines E S, 'l-l, 8--8 and 9-9- respectively.

R ferrin now indetail-to the illustrat d preferred embodiment of thepresentginventiomlike reference characters areusedthroiighout toillustrate similar elements. This invention has been conceived anddeveloped 'to fill the need "for trench d-i'ggerblades-for useintrenchers of relatively Slight *constr-uction having limited powercapacity and-which-m-aybe s0ld:at a fraction of swin in {movemen sis :3z am viii Th latter may hezleweted int th r ll t ed e n -e si tion by:meansof a yh-and-wheel 7 2t which serves to vretate ,asSE 1 k "WhQ '2"c ed ri y to Sim-bea ljen ridles d ep fidieser' ain =24 is trainedabout t e be m ten u tab :Sprocket wheels jeni naledeat eachrendthereef. Esra-detaile idescriptienzo t aiira-nd its as at d support nracemes/dinn ngele ent e made {to ccpending repplication Serial No.755,825 filed JunebZQ, 18,47, aof which :thiscase is e ;,divis ion. ,{Itwill esnfiice {to say -.that stepelewn -,-dri:vin.Gflnnecti-oniaprovided between I the el pulley drivelilt n the h n-tflhs-c u s lipwarshmovem n ve ztheisiise bl e a ne th frentasell e Qfif thejcearn l-8 asrthe; latter :i moved s-lpwlsr. h1;oad=. .isqinto-a-,;g'ag-ement with theearth.

hemovement of the vein-clef n1 ay. beprodueed ei er ley the vehiclevh-eelsiorzhy a eable and iate t ii eon-erred :b t e i l en e s hewn Fi:21) th Win h 2 -210m ea the forward end of the vehicle and power issupplied thereto by means of a reciprocating rod 28 which extends alongthe vehicles underside. Since both the vehicle drive and the drive forthe digger blades are effected by the same power source, it will beapparent that the cutting speed of the blades against the earth iscoordinated with the forward speed of the vehicle. The earth which isdrawn to the surface as the result of the action of thedigger blades isspread laterally away from the trench by the augers 30, 32.

In accordance with the invention, the chain 24 is provided withalternate right and left-hand cutter blades arranged to extend bothradially and laterally outward from the loop of chain 24 as shown inFigs. 1a, 2, 3 and 4. The blades are formed of metal plates each havinga base which is fastened to the side wall of the chain and a bodyportion which curves smoothly inwardly toward the axis of the chain. Inpracticing the invention the curved blades each have a sharpened leadingedge and a trailing edge in general alinement with the leading edge, theportion between the edges being smooth and uninterrupted byearth-catching pocketsor the like. Further in accordance with theinvention the cutting edges of the successive right and left-hand bladesare located at different distances laterally with respect to the chainso that the pairs of blades have a different lateral width or span.

The blades used in the present embodimentfall into two generalcategories. Thus one pair of cutter blades 40, 4! have an over-all widthwhich is substantially equal to that of the chain with the free orleading edges thereof reaching substantially to the center of the chainand even overlapping slightly. It will be apparent that these bladesacting alone would be capable of producing a channel in the earth whichis sufiiciently wide for the admission of the chain. These may forpurposes of convenience be termed center cutters.

Another pair of right and left-hand cutter blades 42, .3, although ofthe same general shape, have a greater width or span and tend to broadenthe channel cut by the blades of lesser span. Because of the fact thatthe blades project laterally from the chain 24 by differing amounts, theaction on the earth is obviously quite analogous to that of broaching inmachine tool practice. Since the bite of each successive blade islimited, a trench of considerable width may be out without any undueloading on the individual blades.

Referring now to the means used for mounting the blades, it will benoted that each blade has a base 45 which lies flatly against the sidesof the chain and has suitable apertures formed therein through which theconventional roller bearing pins 41 extend. Each blade has in addition arearwardly extending heel portion 50 as shown in Fig. 3 which overlapsthe subsequential link in the chain to rigidify the mounting and preventskewing of the blade as the leading edge portion thereof is engaged bythe earth.

In operation, it is found that loosened earth is efficiently lifted aswell as cut. One might well wonder how the cutter blades, being arrangedin non-opposing relation on a chain free of scoops, buckets and thelike, can be effective to clear the trench of earth. Although a largeproportion of the loosened earth will obviously fall free of the cutterblades, it must eventually reach the surface for the device to operate.fact that it does, with substantially no delay, can

The

only be explained by the repeated urging or impact imparted to the earthby the successive blades and the drag of the chain itself. The fact thatthe channel cut by the blades is considerably inclined undoubtedly aidsthis process. A further clue to the successful operation appears in Fig.4. where it will be noted that the upwardly projected area of the bladesof unlike width is much greater than that which would obtain if all theblades were in perfect alinement along the chain.

It will be apparent that with no pockets in the blades to fill up withthe loosened earth, the jammin and clogging associated with bucket typecutters, particularly under wet and clayey conditions, cannot occur.Further, in conventional buckets the earth must be carried to the top ofthe loop of chain before the bucket is inverted and the earth allowed tospill out. Here, in the absence of buckets, the earth must be freed atthe point of exit, in other words, at or only slightly above the surfaceof the earth in position to be immediately removed by the augerconveyors. y

In the following claim the term successive links when referring to thesprocket chain, shall be taken to mean links that follow one another butare not necessarily adjacent to one another.

I claim as my invention:

For use in a trencher having a beam arranged to extend rearwardly anddownwardly therefrom into the earth and having an endless driven loop ofsprocket chain surrounding the same and trained about the ends thereof,a first pair of right and left-hand digger blades, each having a baseproviding a mounting surface for mounting the blades alternately and onthe side walls of successive links of said sprocket chain, said diggerblades each having a cutting portion in the form of a plate of metalsharpened at the leading edge and smoothly curved inwardly toward thecenter line of said sprocket chain, the blades having a span which is upto a small amount wider than the width of said chain, a second pair ofright and left-hand digger blades having bases for alternate mounting ofthe blades on successive links of said chain similarly to the blades ofsaid first pair, said second pair of digger blades each having a body inthe form of a curved plate of metal sharpened at the leading edge andconcaved inwardly toward the center line of said sprocket chain buthaving a greater lateral span so as to broach out the channel cut bysaid first pair of digger blades.

FRIEDRICH J. SCHMIDT.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name 'Date 646,674 Bentson Apr. 3, 19001,745,090 Geithle Jan. 28, 1930 1,885,382 Dunlap Nov. 8, 1932 2,114,129Younie Apr. 12, 1938 FOREIGN PATENTS Number Country Date 591,962 GermanyJan. 30, 1934

